LED Array
Array of strings
Enter supply, per-LED VF, LEDs per string and current; per-string resistor and total power appear live.
Array sizing
How to use this calculator
An LED array is typically several series strings in parallel, each with its own current-limiting resistor. Each string's resistor is R = (Vcc − n·VF) / I. Enter the supply, per-LED forward voltage, LEDs per string, and the current per string; the per-string resistor and the total array power (all strings together) appear live.
What it means in a real circuit
For a 12 V supply, 2 V LEDs, 3 per string and 20 mA, each string needs a 300 Ω resistor, and the array power scales with the number of parallel strings (each string ≈ 12 V × 20 mA = 240 mW). Parallel strings are the practical way to get many LEDs on one supply while keeping each string's current controlled. Use this to plan panel or sign lighting and to size the supply current and the resistors' power ratings.